title: Enhanced visible-light hydrogen-production activity of copper-modified ZnxCd(1-x)S.
abstract: Copper modification is an efficient way to enhance the photocatalytic activity of ZnS-based materials; however, the mechanisms of Cu(2+) surface and bulk modifications for improving the activity are quite different. In this work, two different synthetic pathways were devised to prepare surface and bulk Cu(2+)-modified Znx Cd1-x S photocatalysts through cation-exchange and coprecipitation methods, respectively. Different Cu(2+) modifications brought different effects on the phase structure, morphology, surface area, optical property, as well as the photocatalytic H2-production activity of the final products. The optimized Cu(2+)-surface-modified Znx Cd1-x S photocatalyst has a high H2-production rate of 4638.5 μmolh(-1) g(-1) and an apparent quantum efficiency of 20.9% at 420 nm, exceeding that of Cu(2+)-bulk-modified catalyst at the same copper content. Cu(2+) surface modification not only brings a new electron-transferring pathway (interfacial charge transfer), but also produces new surface active sites for H2 evolution, reducing the recombination rate of photogenerated charge carriers.
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (P.R. China); School of Chemical Engineering, The University of Adelaide, SA 5005 (Australia).
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.forename: Quanlong
authors.initials: Q
authors.lastname: Xu
authors.forename: Shi Zhang
authors.initials: SZ
authors.lastname: Qiao
authors.forename: Jiaguo
authors.initials: J
authors.lastname: Yu
mesh_terms: D002104:Cadmium / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D008027:Light; D013440:Sulfides / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
chemical_list: D013440:Sulfides; D002104:Cadmium; D003300:Copper; D006859:Hydrogen; D015032:Zinc
keywords: charge transfer; copper; hydrogen; photochemistry; water splitting